1 package antlr;
2
3 * <b>SOFTWARE RIGHTS</b>
5 * <p>
6 * ANTLR 2.5.0 MageLang Institute, 1998
7 * <p>
8 * We reserve no legal rights to the ANTLR--it is fully in the
9 * public domain. An individual or company may do whatever
10 * they wish with source code distributed with ANTLR or the
11 * code generated by ANTLR, including the incorporation of
12 * ANTLR, or its output, into commerical software.
13 * <p>
14 * We encourage users to develop software with ANTLR. However,
15 * we do ask that credit is given to us for developing
16 * ANTLR. By "credit", we mean that if you use ANTLR or
17 * incorporate any source code into one of your programs
18 * (commercial product, research project, or otherwise) that
19 * you acknowledge this fact somewhere in the documentation,
20 * research report, etc... If you like ANTLR and have
21 * developed a nice tool with the output, please mention that
22 * you developed it using ANTLR. In addition, we ask that the
23 * headers remain intact in our source code. As long as these
24 * guidelines are kept, we expect to continue enhancing this
25 * system and expect to make other tools available as they are
26 * completed.
27 * <p>
28 * The ANTLR gang:
29 * @version ANTLR 2.5.0 MageLang Institute, 1998
30 * @author Terence Parr, <a href=http://www.MageLang.com>MageLang Institute</a>
31 * @author <br>John Lilley, <a href=http://www.Empathy.com>Empathy Software</a>
32 */
33 * is only one alternative (i.e., a list of children). We subclass to
35 * specialize. MakeGrammar.addElementToCurrentAlt will work correctly
36 * now for either a block of alts or a Tree child list.
37 *
38 * The first time addAlternativeElement is called, it sets the root element
39 * rather than adding it to one of the alternative lists. Rather than have
40 * the grammar duplicate the rules for grammar atoms etc... we use the same
41 * grammar and same refToken behavior etc... We have to special case somewhere
42 * and here is where we do it.
43 */
44 class TreeBlockContext extends BlockContext {
45 protected boolean nextElementIsRoot = true;
46
47
48 public void addAlternativeElement(AlternativeElement e) {
49 TreeElement tree = (TreeElement)block;
50 if ( nextElementIsRoot ) {
51 tree.root = (GrammarAtom)e;
52 nextElementIsRoot = false;
53 }
54 else {
55 super.addAlternativeElement(e);
56 }
57 }
58 }
59